An off-duty University of Texas police officer shot and killed an intruder he struggled with Monday in a Houston apartment complex, police said.

The officer, who was not identified, was working an off-duty security job at the Arcadian Apartments at 7550 Kirby when management called him to investigate a report of a break-in about 1:35 p.m. at one of the apartments, Houston Police Department spokeswoman Jodi Silva said.

"It looks like the officer was called by the leasing office. He went there and saw the door had been kicked in," Silva said.

The officer went inside the apartment and confronted the intruder, Silva said, and the two began to struggle. "So at that point, he was in fear of his safety and his life and so he discharged his duty weapon," she said.

Silva said it was unknown if the intruder was armed during the struggle.

Cavazos said the officer was a seven-year veteran of the department and was working an extra job that had been approved by the department. The officer had received a "considerable" amount of firearms training by the department, Cavazos said.

Cavazos declined to release the name of the officer, adding he did not know the extent of his injuries or his condition.